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When Does Intermittent Fasting Start Working?

People often desire fast results, especially when it comes to shedding pounds. Intensive methods are often chosen with the hope of becoming fit again quickly. However, immediate results rarely mean something healthy. 

Some think that intermittent fasting is one of the efficient strategies to lose weight fast, enhance gut health immediately, or just to have better heart health promptly. Yet intermittent fasting is not centered on the speed of your results, it has to do with the quality of the food you eat on the non-fasting days and your general lifestyle. 

And no, intermittent fasting is not a magic pill for alleviating all the symptoms. It’s a serious decision to make, preferably under the supervision of your healthcare provider. Intermittent Fasting For Women and men may provide many benefits. But how quickly? 

Put your mind at ease, I’ve put together this article to demonstrate to you that intermittent fasting methods, whether it’s a 16/8 fasting, or an alternate day fast actually work, relative to time and healthy choices. 

When does Intermittent fasting start working? Study this article and disclose the answer yourself. 

How long does intermittent fasting take to show results?

Obviously, intermittent fasting is gaining in popularity, especially among weight loss enthusiasts. Intermittent fasting entails not eating for a certain period of time each day or week (19). 

Now let’s dig deeper into the expected results. The truth that lies behind this question is simple: results will be different for each person. Besides, not everyone enters fasting to lose weight. Someone wants to promote gut health, while another is eager to reduce inflammation. 

Besides, intermittent fasting relies on your dietary choices, and how actively you live your life. 

In general, people who try fasting notice its results after the first few days. A 2022 literature review found that a single fast could alter sugar and fat metabolism, at least temporarily (15).

I’m sure this information may not be enough for you. With that in mind, I’ve put together a chart summarizing what the research says about fasting benefits and the period of time it may take to notice results:

Period of intermittent fasting The possible benefit
One month • Enhanced liver function (17) • Improved levels of hormones to regulate appetite (8)
Two months • Lower fat mass (with IF + HIIT exercise) (3) • Better athletic performance (with IF + HIIT exercise) (3) • Improved gut microbial composition (12) • Enhanced production of short-chain fatty acids (the leading source of energy for the cells of your colon) (12)
Three months • Weight loss and lower body mass index (BMI) (6) • Promoted insulin sensitivity and lower insulin levels (6) • Increased muscle strength (IF + resistance training) (10)
Long-term • Decreased risk of type 2 diabetes (11) • Lowered risk of heart disease (13) • Promoted athletic endurance (18) • Reduced inflammation (5) • Improved blood pressure(2)

From the chart you can see that intermittent fasting, before and after you try it, can potentially boost your health. However, it’s still unclear what the long-term effects and safety factors are for intermittent fasting. . 

Always consult with your healthcare provider before beginning a fasting regimen, as medical conditions and medication use must be taken into consideration, and some people should not fast. 

See also
Can Intermittent Fasting Cause Weight Gain?

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How do you know if intermittent fasting is working?

Okay, there is a difference between the benefits on paper and in real life. That’s why you may not even know if intermittent fasting is working, or can you? 

In fact, if you do everything right, you might notice some changes. These changes show you that your intermittent fasting is really working. Let’s look through the potential changes more deeply: 

  1. Weight loss
  2. Sleeping better
  3. More energy
  4. Improved medical markers
  5. Better mood

Weight loss

Try to wear the jeans you couldn’t fit in, or your bra that seemed to be too tight. If it gets easier to wear, this demonstrates you’ve lost some weight. The thing you should always keep in mind is that the best intermittent fasting for weight loss is not going to be successful without putting in additional effort: 

  • sleep well
  • staying hydrated
  • eating nutritious food during eating windows
  • exercising

Sleeping better

Pay attention to how easily you fall asleep. If you stopped turning in your bed from side to side or staring at the ceiling without your eyes shut then you’ve progressed. 

Of course there are harmful habits responsible for sleep deprivation, such as spending time on your phone or in front of your laptop before going to bed. 

when does intermittent fasting start working  

More energy

Yes, at first you won’t feel invigorated during the intermittent fasting period. But gradually, once your body gets used to it, you should gain more energy to do things. Besides, only with better sleep and you are already guaranteed to have a much more productive day. 

Improved medical markers

You already know that intermittent fasting could be beneficial for your blood pressure and blood sugar levels. Check your blood pressure at home and compare the results with the numbers you had before your intermittent fasting spree. It’s also good to go to the local clinic to see how well the blood sugar levels are maintained. 

See also
How to Fast Properly to Reap Wellness Rewards

Better mood

At the beginning of your intermittent fasting periods you may become irritable and face a number of mood swings. This happens due to tiredness and fatigue, as your body is shocked for not getting food for longer periods. 

Once you overcome this excruciating point, you may feel stronger. You may begin to sleep better, which leads to a higher level of energy, and the more energy you have, the better your mood will be. This chain never stops working as you sustain it with beneficial lifestyle choices. 

Read more: Is Fasting for 24 Hours Once a Week Healthy?

At what hour does fat burning start when intermittent fasting?

Weight loss is one of the main reasons to try an Intermittent fasting regime. Your metabolic system is responsible for changing the foods and beverages you consume into energy. Most of the time, your body receives its energy from a sugar called glucose. You can find glucose in the meals you eat and beverages you drink. 

Since you’re eating and drinking frequently, your body maintains a steady glucose supply. The situation alters when you start fasting as when you stop eating food for a longer period of time. You no longer get glucose from outside sources. First it will start using its stored glucose, which is in the form of glycogen. 

Once glycogen is depleted, it uses fat for energy. Fat tissue is broken down into fatty acids and released into the blood (14). The liver metabolizes them and produces a chemical called ketones, which your body uses as an energy source. 

I explained this process so that you could get a clear idea of what happens to your body if you don’t consume food. However, to achieve ketosis you’ll likely need to fast for at least 12 hours, possibly longer. The exact time it takes may vary. 

Additionally, it would be beneficial for you to try the Intermittent Fasting Exercise. Combining fasting with moderate training increases your chances of trimming extra fat. Try to workout during your eating window, or if you do fasted exercise, don’t push yourself too hard. . 

How long does it usually take to lose weight on intermittent fasting?

One review in 2015 found that alternate-day fasting trials lasting 3-12 weeks appeared to be effective at reducing body weight, while whole-day fasting trials lasting from 12-24 weeks also seemed to be effective (7).

See also
What Can You Drink During Intermittent Fasting?

However, the results will never be the same for everyone. Many individual factors influence weight loss.   

Maintaining a healthy weight is not about how often you’re able to abstain from food. What and how much you eat during your eating window as well as other lifestyle factors are even more important. Try asking yourself these questions: : 

  1. Am I active enough in my life? 
  2. Am I choosing mostly healthy food or overeating?
  3. Do I sleep well? 
  4. Am I hydrated enough, or should I drink more?
  5. Do I deal with stress often? 
  6. How can I make myself feel better healthily? 

To lose weight you’ll need to eat fewer calories overall than you burn. It’s helpful to eat healthy balanced meals with an emphasis on fruits and vegetables. whole grains, legumes, lean proteins, and healthy fats. Staying physically active, managing stress, getting good sleep and staying hydrated are also important. 

when does intermittent fasting start working  

What is the best fasting for a beginner?

I’m not going to review all the fasting methods since I’m sure you’re aware of all of them. With regard to the best option for beginners, you might want to focus on two types of fasting (16): 

  • Fast for 12 hours a day. It’s the first type of fasting that requires abstaining from food for 12 hours. It’s beneficial for beginners as you can include your sleep in the fasting window. An example of this fast may look like this: you don’t eat from 7 PM to 7 AM. Therefore, you should finish your dinner before 7 PM and wait till 7 AM for your breakfast. 
  • Fast for 16 hours. This method is popularly called intermittent fasting 16:8. Sometimes this regime involves males fasting for 16 hours while females fasting for 14 hours. In one example of a schedule for this fast, you need to finish your evening meal by 8 PM, and then skip breakfast the next day, not eating anything until noon.

It’s good to start a 16:8 fasting method only after you’ve tried the 12-hour fasting regime. Beginners may reap a lot of benefits from these fasting strategies alongside a healthy diet in their feeding windows, sleeping enough, and staying active. 

Please note that fasting regimens are not suitable for everyone. There are people who should avoid any type of fasting. They are:

  • Children under 18
  • Elderly people
  • People who have a history of eating disorders
  • People with health conditions, like diabetes or who are on certain medications (discuss with your healthcare provider)
  • Breastfeeding and pregnant females (16).
See also
Carb Cycling and Intermittent Fasting: Can You Do Both?

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Will 5 calories break a fast? 

What Breaks A Fast? The question is asked mostly by beginners. Will sweet coffee count as a fast breaker? Can I have sugar soda? There is a general misconception that only food can load you with calories. Funny though, there are still people who believe that alcohol doesn’t affect weight, as well as sugary beverages. 

You don’t only get calories from your food but also from certain types of drinks as well. 

The strict reality of it is simple: any type of food or drink containing calories breaks a fast. Therefore, on your fasting window, you shouldn’t consume any foods as well as beverages that contain calories. 

You can drink water and unsweetened tea or coffee without added milk or cream. 

Besides, staying hydrated might help reduce your cravings. So, when another thought about a tasteful meal pops into your head, have some water, and you may feel better. 

How many days a week should you do 16-8 intermittent fasting?

Since this type of fasting is relatively safe and even advised for beginners, people are allowed to do it frequently – from once to twice per week, up to every day. Your frequency entirely depends on how you feel during this time. 

Try to do it for two days per week, and when feeling okay shift to more frequent fasting periods, gradually moving to your daily regime. 

Why I stopped intermittent fasting? 

Intermittent fasting can have adverse side effects: dehydration, weakness, low blood pressure, or excessive weight loss. Fasting can be challenging enough, especially for beginners. Therefore, stopping the process when you experience one or all the symptoms sounds reasonable. 

You shouldn’t exasperate your body with intermittent fasts if the adverse effects continue. Instead, cease the process and talk to your doctor to ensure your health is not at risk. 

Read more: Intermittent Fasting Cortisol: Should You Fast?


What are the 5 stages of intermittent fasting?

During the first stage, your body uses all the nutrients from the previous meal; in the second stage, your insulin and glucose levels lower and you start using your stored glucose (glycogen); in the third stage, your body starts searching for energy through other sources; during the fourth stage, your body starts using fat cells as energy; and in the final fifth stage, you reintroduce your body to food again. 

See also
Endomorph Intermittent Fasting: How It Works

How many pounds can you lose in 30 days with intermittent fasting?

It depends on your lifestyle and dietary choices on your feeding window. If you stay active, eat healthily, and follow all the guidelines of intermittent fasting, you might lose up to 4-8 pounds per month (1-2 pounds per week). 

How many days a week should I intermittently fast?

In this case, your frequency of fasting days depends on the fasting regime you choose. There are different approaches to intermittent fasting. The 4-week 16:8 fasting as well as the 12-hour fasting regime allows you to do it daily. Nonetheless, the more extreme fasts, like a 24-hour fast should be done not more than two times per week. That’s why you need to figure out the fasting strategy first and then analyze your frequency. 

The Bottom Line

When does Intermittent fasting start working? Finally, you reached the end of the article and hopefully have a clearer idea of when to expect the results from intermittent fasting. Let’s flick through the major points from the piece.

You might reap a bunch of benefits from intermittent fasting beginning from weight loss to promoting heart health. The results may start to be visible during the first month of your intermittent fasting regime. However, many other factors affect the speed of the coming results: the food you eat on your feeding window, how actively you move through your days, and the quality of your sleep, and individual factors.

In regards to weight loss, you might start burning fat after at least 12 hours of fasting. If you are aiming for weight loss, you still need to eat fewer calories overall than you burn, and you should expect a safe and sustainable pace of 1-2 pounds per week.

The best-fasting regimens for beginners involve a 12-hour fast and a 16:8 method. You shouldn’t get into intermittent fasting without consulting your doctor. Under their supervision, you may reap the benefits without the extreme consequences. 


This article is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional advice or help and should not be relied on to make decisions of any kind. Any action you take upon the information presented in this article is strictly at your own risk and responsibility!


  1. Do intermittent diets provide physiological benefits over continuous diets for weight loss? A systematic review of clinical trials (2015,
  2. Effect of Epidemic Intermittent Fasting on Cardiometabolic Risk Factors: A Systematic Review and Meta-Analysis of Randomized Controlled Trials (2021,
  3. Effect of High-Intensity Interval Training and Intermittent Fasting on Body Composition and Physical Performance in Active Women (2021,
  4. Effects of fasting therapy on irritable bowel syndrome (2006,
  5. Effects of intermittent fasting diets on plasma concentrations of inflammatory biomarkers: A systematic review and meta-analysis of randomized controlled trials (2020,
  6. Effects of Intermittent Fasting in Human Compared to a Non-intervention Diet and Caloric Restriction: A Meta-Analysis of Randomized Controlled Trials (2022,
  7. Effects of intermittent fasting on body composition and clinical health markers in humans (2015,
  8. Effects of Ramadan Intermittent Fasting on Gut Hormones and Body Composition in Males with Obesity (2020,
  9. Fasting as a Therapy in Neurological Disease (2019,
  10. Intermittent fasting and continuous energy restriction result in similar changes in body composition and muscle strength when combined with a 12 week resistance training program (2022,
  11. Intermittent Fasting and Metabolic Health (2022,
  12. Intermittent Fasting Improves Cardiometabolic Risk Factors and Alters Gut Microbiota in Metabolic Syndrome Patients (2021,
  13. Intermittent Fasting in Cardiovascular Disorders-An Overview (2019,
  14. Intermittent Fasting: Is it Right for You? (2019,
  15. Physiological responses to acute fasting: implications for intermittent fasting programs (2022,
  16. Six ways to do intermittent fasting (2023,
  17. The effects of Ramadan intermittent fasting on liver function in healthy adults: A systematic review, meta-analysis, and meta-regression (2021,
  18. Time-Restricted Feeding and Aerobic Performance in Elite Runners: Ramadan Fasting as a Model (2021,
  19. What is intermittent fasting? Does it have health benefits? (2022,
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